//go:build unix

package diary_test

import (
	"os"
	"path/filepath"
	"slices"
	"strings"
	"syscall"
	"testing"

	"git.golem15.com/golem15/summercms/modules/diary"
)

// dailyOnly is the environment of a configuration whose default channel is
// the daily file at info.
var dailyOnly = []string{"SUMMER_LOG__DEFAULT=daily", "SUMMER_LOG__CHANNELS__DAILY__LEVEL=info"}

// TestDailyRotation: a record before and one after local midnight land in
// two files named by their dates.
func TestDailyRotation(t *testing.T) {
	root := t.TempDir()
	clk := newClock(day(21, 23, 59, 59))
	var buf lockedBuffer
	setup(t, diary.Options{Stderr: &buf, Root: root, Now: clk.Now}, dailyOnly...)
	blog := diary.For("blog")

	blog.Info("before midnight")
	clk.Set(day(22, 0, 0, 1))
	blog.Info("after midnight")

	dir := filepath.Join(root, "storage", "logs")
	first := readDaily(t, filepath.Join(dir, "summer-2026-10-21.log"))
	second := readDaily(t, filepath.Join(dir, "summer-2026-10-22.log"))
	if len(first) != 1 || !strings.Contains(first[0], "before midnight") {
		t.Errorf("2026-10-21 file = %q, want only the record before midnight", first)
	}
	if len(second) != 1 || !strings.Contains(second[0], "after midnight") {
		t.Errorf("2026-10-22 file = %q, want only the record after midnight", second)
	}
	if buf.String() != "" {
		t.Errorf("console written although the default channel is daily:\n%s", buf.String())
	}
}

// TestDailyRetention: with days 2 the files of today and the day before are
// kept, older files of the same base are deleted, and every other file in
// the directory is left alone. days 0 keeps everything.
func TestDailyRetention(t *testing.T) {
	keep := []string{
		"summer-2026-10-20.log", "summer-2026-10-21.log",
		"summer.log", "other-2026-10-01.log", "summer-2026-10-01.json",
		"summer-latest.log", "summer-2026-1-1.log", "notes.txt", "xsummer-2026-10-01.log",
	}
	gone := []string{"summer-2026-10-19.log", "summer-2026-10-18.log", "summer-2025-01-01.log"}

	prepare := func(t *testing.T) string {
		t.Helper()
		root := t.TempDir()
		dir := filepath.Join(root, "storage", "logs")
		if err := os.MkdirAll(filepath.Join(dir, "summer-2026-10-01.log"), 0o750); err != nil {
			t.Fatal(err)
		}
		for _, name := range append(slices.Clone(keep), gone...) {
			if err := os.WriteFile(filepath.Join(dir, name), []byte("old\n"), 0o640); err != nil {
				t.Fatal(err)
			}
		}
		return root
	}
	list := func(t *testing.T, root string) []string {
		t.Helper()
		entries, err := os.ReadDir(filepath.Join(root, "storage", "logs"))
		if err != nil {
			t.Fatal(err)
		}
		var names []string
		for _, e := range entries {
			names = append(names, e.Name())
		}
		return names
	}

	root := prepare(t)
	setup(t, diary.Options{Root: root, Stderr: &lockedBuffer{}},
		append(slices.Clone(dailyOnly), "SUMMER_LOG__CHANNELS__DAILY__DAYS=2")...)
	diary.For("blog").Info("today")
	names := list(t, root)
	for _, name := range append(slices.Clone(keep), "summer-2026-10-01.log") {
		if !slices.Contains(names, name) {
			t.Errorf("retention deleted %s; left %v", name, names)
		}
	}
	for _, name := range gone {
		if slices.Contains(names, name) {
			t.Errorf("retention kept %s; left %v", name, names)
		}
	}
	today := readDaily(t, filepath.Join(root, "storage", "logs", "summer-2026-10-21.log"))
	if len(today) != 2 || today[0] != "old" || !strings.Contains(today[1], `"msg":"today"`) {
		t.Errorf("today's file = %q, want the old line and the new record appended", today)
	}

	diary.Reset()
	root = prepare(t)
	setup(t, diary.Options{Root: root, Stderr: &lockedBuffer{}},
		append(slices.Clone(dailyOnly), "SUMMER_LOG__CHANNELS__DAILY__DAYS=0")...)
	diary.For("blog").Info("today")
	names = list(t, root)
	for _, name := range append(slices.Clone(keep), gone...) {
		if !slices.Contains(names, name) {
			t.Errorf("days 0 deleted %s", name)
		}
	}
}

// TestDailyPermissions: a new daily file is 0640 whatever the umask, its
// directory 0750 under the usual umask, and an existing file keeps its mode.
func TestDailyPermissions(t *testing.T) {
	old := syscall.Umask(0o022)
	t.Cleanup(func() { syscall.Umask(old) })

	root := t.TempDir()
	setup(t, diary.Options{Root: root, Stderr: &lockedBuffer{}}, dailyOnly...)
	diary.For("blog").Info("first")
	dir := filepath.Join(root, "storage", "logs")
	file := filepath.Join(dir, "summer-2026-10-21.log")
	readDaily(t, file)
	assertMode(t, file, 0o640)
	assertMode(t, dir, 0o750)

	// A strict umask cannot strip the file's group read bit.
	diary.Reset()
	syscall.Umask(0o077)
	root = t.TempDir()
	setup(t, diary.Options{Root: root, Stderr: &lockedBuffer{}}, dailyOnly...)
	diary.For("blog").Info("strict umask")
	file = filepath.Join(root, "storage", "logs", "summer-2026-10-21.log")
	readDaily(t, file)
	assertMode(t, file, 0o640)

	// An existing file is appended to and keeps its mode.
	diary.Reset()
	syscall.Umask(0o022)
	root = t.TempDir()
	dir = filepath.Join(root, "storage", "logs")
	if err := os.MkdirAll(dir, 0o750); err != nil {
		t.Fatal(err)
	}
	file = filepath.Join(dir, "summer-2026-10-21.log")
	if err := os.WriteFile(file, nil, 0o600); err != nil {
		t.Fatal(err)
	}
	setup(t, diary.Options{Root: root, Stderr: &lockedBuffer{}}, dailyOnly...)
	diary.For("blog").Info("existing")
	if lines := readDaily(t, file); len(lines) != 1 {
		t.Errorf("existing file has %d lines, want 1", len(lines))
	}
	assertMode(t, file, 0o600)
}

func assertMode(t *testing.T, path string, want os.FileMode) {
	t.Helper()
	info, err := os.Stat(path)
	if err != nil {
		t.Fatal(err)
	}
	if got := info.Mode().Perm(); got != want {
		t.Errorf("%s mode = %o, want %o", path, got, want)
	}
}

// TestDailyUnwritable: a daily file that cannot be opened warns once (on a
// plain stderr handler when no console channel exists), never fails Setup,
// and later records are dropped silently.
func TestDailyUnwritable(t *testing.T) {
	root := t.TempDir()
	// A regular file where the log directory should be: MkdirAll fails for
	// every user, root included.
	if err := os.WriteFile(filepath.Join(root, "blocker"), []byte("x"), 0o600); err != nil {
		t.Fatal(err)
	}
	var buf lockedBuffer
	setup(t, diary.Options{Root: root, Stderr: &buf},
		append(slices.Clone(dailyOnly), "SUMMER_LOG__CHANNELS__DAILY__PATH=blocker/logs/summer.log")...)
	blog := diary.For("blog")
	for i := range 5 {
		blog.Info("record", "i", i)
	}
	out := buf.String()
	if n := strings.Count(out, "daily log file disabled"); n != 1 {
		t.Fatalf("warning appears %d times, want 1:\n%s", n, out)
	}
	for _, want := range []string{"level=WARN", "component=diary", filepath.Join(root, "blocker", "logs", "summer-2026-10-21.log")} {
		if !strings.Contains(out, want) {
			t.Errorf("warning lacks %q:\n%s", want, out)
		}
	}
	if strings.Contains(out, "msg=record") {
		t.Errorf("records reached stderr although the default channel is daily:\n%s", out)
	}
	if err := diary.Close(); err != nil {
		t.Errorf("Close after a disabled daily file: %v", err)
	}
}

// TestDailyLazyOpen: no file or directory exists until a record reaches the
// daily channel; a closed file opens again on the next record.
func TestDailyLazyOpen(t *testing.T) {
	root := t.TempDir()
	var buf lockedBuffer
	setup(t, diary.Options{Root: root, Stderr: &buf})
	storage := filepath.Join(root, "storage")
	if _, err := os.Stat(storage); !os.IsNotExist(err) {
		t.Fatalf("Setup created %s (err %v)", storage, err)
	}
	diary.For("blog").Info("below the daily level")
	if _, err := os.Stat(storage); !os.IsNotExist(err) {
		t.Fatalf("an info record created %s although the daily level is warn (err %v)", storage, err)
	}
	if !strings.Contains(buf.String(), "below the daily level") {
		t.Errorf("console lacks the info record:\n%s", buf.String())
	}

	file := filepath.Join(storage, "logs", "summer-2026-10-21.log")
	diary.For("blog").Warn("first warning")
	if lines := readDaily(t, file); len(lines) != 1 {
		t.Fatalf("daily file has %d lines after one warning, want 1", len(lines))
	}
	diary.For("blog").Warn("after close")
	if lines := readDaily(t, file); len(lines) != 2 {
		t.Fatalf("daily file has %d lines after reopening, want 2", len(lines))
	}
}

// TestPathConfinement: a relative daily path may not leave the application
// root; a path that stays inside after cleaning and an absolute path are
// accepted, and relative paths resolve against Options.Root.
func TestPathConfinement(t *testing.T) {
	for _, path := range []string{"../summer.log", "storage/../../summer.log", "./../logs/summer.log", ".."} {
		_, err := diary.ParseConfig(openConfig(t, "SUMMER_LOG__CHANNELS__DAILY__PATH="+path))
		if err == nil || !strings.Contains(err.Error(), "log.channels.daily.path") {
			t.Errorf("path %q: err %v, want an error naming log.channels.daily.path", path, err)
		}
	}

	abs := filepath.Join(t.TempDir(), "elsewhere", "app.log")
	for _, path := range []string{"storage/../logs/summer.log", "logs/app.log", abs} {
		if _, err := diary.ParseConfig(openConfig(t, "SUMMER_LOG__CHANNELS__DAILY__PATH="+path)); err != nil {
			t.Errorf("path %q rejected: %v", path, err)
		}
	}

	root := t.TempDir()
	setup(t, diary.Options{Root: root, Stderr: &lockedBuffer{}},
		append(slices.Clone(dailyOnly), "SUMMER_LOG__CHANNELS__DAILY__PATH="+abs)...)
	diary.For("blog").Info("absolute")
	if lines := readDaily(t, filepath.Join(filepath.Dir(abs), "app-2026-10-21.log")); len(lines) != 1 {
		t.Errorf("absolute path file has %d lines, want 1", len(lines))
	}

	diary.Reset()
	setup(t, diary.Options{Root: root, Stderr: &lockedBuffer{}},
		append(slices.Clone(dailyOnly), "SUMMER_LOG__CHANNELS__DAILY__PATH=storage/../logs/app.log")...)
	diary.For("blog").Info("relative")
	if lines := readDaily(t, filepath.Join(root, "logs", "app-2026-10-21.log")); len(lines) != 1 {
		t.Errorf("relative path did not resolve against the root: %d lines", len(lines))
	}
}